The invention generally relates to call control processing in a communications network and more specifically to a method and apparatus for implementing subscriber permissions and restrictions for switched connections in a digital communications network.
Differing communication systems employ various methods for partitioning bandwidth amongst calls routed through a network. In asynchronous transfer mode (ATM) networks, for instance, when a switched connection such as a switched virtual circuit (SVC) is established the call set-up message carries a number of information elements (IEs) which specify various traffic and quality of service (QoS) parameters. This information is processed by call control software resident on each network node which determines the type or service category of the requested connection as well as the bandwidth required by the connection. The connection admission control (CAC) function of the node is then executed in order to determine whether the node has sufficient internal resources such as bandwidth and buffer space to support the requested call. If so, the node reserves internal bandwidth and buffer space for that connection and the call set-up message is progressed to the next node along the path of the switched connection.
Once the switched connection has been established, the ingress node (of the network) typically applies a usage parameter control (UPC) function to the connection in order to monitor and police it. More specifically, if the source or customer premise equipment (CPE) misbehaves by transmitting data packets at a rate or with a variability outside of the parameters that the connection was initially set up for, the network may then drop such data packets since they do not conform to the xe2x80x9ctraffic contractxe2x80x9d which was established during call set up.
While the foregoing methodology is effective in policing misbehaving sources once the connection is established. it does not prevent a subscriber from requesting and establishing a switched connection which may require network resources greater than that which has been pre-agreed to via a business or legal arrangement between a subscriber and a network service provider. In other words, no mechanism exists for preventing a subscriber from establishing a switched connection in the first instance using a quantum of network resources beyond that which the subscriber has agreed to pay for.
There are many reasons why subscribers may request service outside of the parameters of a service agreement, including human error in equipment configuration, and wilful intent to defraud. Such erroneous connections, even ones innocently requesting inordinate amounts of bandwidth, are likely to be accepted by the network given the lack of a subscriber enforcement mechanism and the fact that network policies typically permit capacity to be overbooked, often by a 2:1 or 3:1 ratio. Nevertheless, despite such policies, these erroneously configured connections can have a deleterious effect, even if the subscriber equipment is not transmitting data beyond that provided for in the service agreement. This is because high bandwidth connections require large blocks of bandwidth to be reserved for the duration of the connection, independent of how the subscriber uses the available bandwidth. This may result in lost opportunity costs since new traffic may have to be refused if too many erroneous, bandwidth-excessive, connections are provisioned by the network.
The invention enables networking service providers to optionally place limitations on the switched connection requests that subscribers may place on a network. This is accomplished by enabling node administrators to configure, on a per subscriber basis, the throughput limits for all incoming and outgoing switched connections a subscriber may attempt to establish or receive.
One aspect of the invention relates to a method for establishing connections in a switched connection network. The method includes (a) provisioning throughput limitations in respect of network subscribers; (b) requesting the establishment of a switched connection call; (c) filtering the call based on the subscriber throughput limitations; and (d) establishing or refusing to establish the switched connection based on the outcome of the filtering step.
Another aspect of the invention relates to a method of establishing connections in a switched connection communications network. The method includes: (a) provisioning a throughput limitation database in respect of one or more subscribers to the network; (b) signaling a call set-up message in order to establish a switched connection associated with a given subscriber; (c) receiving the call set-up message at an edge network node associated with customer premise equipment of the given subscriber and comparing at least one throughput request provided by the call set-up message against at least one corresponding throughput limitation stored in the database with respect to the given subscriber; and (d) progressing the call set-up message or refusing to establish the switched connection based on the outcome of the comparison.
In the embodiments described herein, the throughput limitation database is stored on an edge network node which carries out the limit checking on a per subscriber basis.